I think anyone attempting to sing those lyrics to other adults would - in most contexts - very rightly meet with surprise and strong disapproval. As you note Steve, it would be especially inappropriate to sing it to children.

It's not just about the power of language to deprave or corrupt - these are words with a great history of violence and systematic oppression attached, towards many of our friends and neighbours. They're words that shouldn't be in use now, and to use them casually in a cultural context normalises their use as a slur.